Denial of Service Vulnerability Affecting Cisco Products

On August 14, 2018, the Vulnerability Coordination team of the National Cyber Security Centre of Finland (NCSC-FI) and the CERT Coordination Center (CERT/CC) disclosed a vulnerability in the IP stack that is used by the Linux Kernel. This vulnerability is publicly known as FragmentSmack.

The vulnerability could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. An attack could be executed by an attacker who can submit a stream of fragmented IPv4 or IPv6 packets that are designed to trigger the issue on an affected device.

The vulnerability is due to inefficient IPv4 and IPv6 fragment reassembly algorithms in the IP stack that is used by the affected kernel. Linux Kernel Versions 3.9 and later are known to be affected by this vulnerability.